* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Home -> Astronomy News -> Mission News -> Deep Impact
Post Info
TOPIC: Deep Impact
Blobrana


L

Posts: 131433
Date:
RE: Deep Impact
Permalink  
 

The Deep Impact spacecraft today will perform a trajectory correction manoeuvre (TCM) to put it into an Earth-return heading, arriving in late 2007 or early 2008.

This will eventually allow a gravity assist to comet Boethin in late 2008.

"This will put the Flyby spacecraft in an orbit path that allows us to contact it at any time. This provides NASA time to investigate opportunities to utilize the Deep Impact spacecraft for future missions" - Monte Henderson, Deputy Director of Programs in Civil Space Systems for Ball Aerospace.


__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

Scientists measure how deep 'Deep Impact' was, with X-rays
Scientists studying the Deep Impact collision using NASA's Swift satellite report that comet Tempel 1 is getting brighter and brighter in X-ray light with each passing day.

The X-rays provide a direct measurement of how much material was kicked up in the impact. This is because the X-rays are created by the newly liberated material lifted into the comet's thin atmosphere and illuminated by the high-energy solar wind from the sun. The more material liberated, the more X-rays are produced.


Expand
7 July: Swift's X-ray detections from Comet Tempel 1 taken before impact



Expand
7 July: Swift's X-ray detections from Comet Tempel 1 taken after impact

Swift data of the water evaporation on comet Tempel 1 also may provide new insights into how solar wind can strip water from planets such as Mars.

"Prior to its rendezvous with the Deep Impact probe, the comet was a rather dim X-ray source. How things change when you ram a comet with a copper probe travelling over 20,000 miles per hour. Most of the X-ray light we detect now is generated by debris created by the collision. We can get a solid measurement of the amount of material released." - Paul O'Brien of the Swift team at the University of Leicester.

"It takes several days after an impact for surface and sub-surface material to reach the comet's upper atmosphere, or coma. We expect the X-ray production to peak this weekend. Then we will be able to assess how much comet material was released from the impact." - Dick Willingale, also of the University of Leicester.

Based on preliminary X-ray analysis, O'Brien estimates that several tens of thousands of tons of material were released, enough to bury Penn State's football field under 30 feet of comet dust. Observations and analysis are ongoing at the Swift Mission Operations Centre at Penn State as well as in Italy and the United Kingdom.

Swift is providing the only simultaneous multi-wavelength observation of this rare event, with a suite of instruments capable of detecting visible light, ultraviolet light, X-rays and gamma rays. Different wavelengths reveal different secrets about the comet.

The Swift team hopes to compare the satellite's ultraviolet data, collected hours after the collision, with the X-ray data. The ultraviolet light was created by material entering into the lower region of the comet's atmosphere; the X-rays come from the upper regions. Swift is a nearly ideal observatory for making these comet studies, as it combines both a rapidly responsive scheduling system with both X-ray and optical/UV instruments in the same satellite.

"For the first time, we can see how material liberated from a comet's surface migrates to the upper reaches of its atmosphere. This will provide fascinating information about a comet's atmosphere and how it interacts with the solar wind. This is all virgin territory" - John Nousek, director of Mission Operations at Penn State.

Nousek said Deep Impact's collision with comet Tempel 1 is like a controlled laboratory experiment of the type of slow evaporation process from solar wind that took place on Mars. The Earth has a magnetic field that shields us from solar wind, a particle wind composed mostly of protons and electrons moving at nearly light speed. Mars lost its magnetic field billions of years ago, and the solar wind stripped the planet of water.

Comets, like Mars and Venus, have no magnetic fields. Comets become visible largely because ice is evaporated from their surface with each close passage around the Sun. Water is dissociated into its component atoms by the bright sunlight and swept away by the fast-moving and energetic solar wind. Scientists hope to learn about this evaporation process on Tempel 1 now occurring quickly -- over the course of a few weeks instead of a billion years -- as the result of a planned, human intervention.

Swift's "day job" is detecting distant, natural explosions called gamma-ray bursts and creating a map of X-ray sources in the universe. Swift's extraordinary speed and agility enable scientists to follow Tempel 1 day by day to see the full effect from the Deep Impact collision.

Swift is a medium-class NASA explorer mission in partnership with the Italian Space Agency and the Particle Physics and Astronomy Research Council in the United Kingdom, and is managed by NASA Goddard. Penn State controls science and flight operations from the Mission Operations Centre in University Park. The spacecraft was built in collaboration with national laboratories, universities and international partners, including Penn State University; Los Alamos National Laboratory, N.M.; Sonoma State University, Rohnert Park, California; Mullard Space Science Laboratory in Dorking, Surrey, England; the University of Leicester, England; Brera Observatory in Milan, Italy; and ASI Science Data Centre in Frascati, Italy.
source

__________________
Blobrana


L

Posts: 131433
Date:
RE: Deep Impact funding
Permalink  
 

According to sources, funding to extend the Deep Impact mission has not (yet) been made available by NASA.
Unless the funds are found, the spacecraft will be placed into a 'safe state' for decommissioning.
The $333 million spacecraft mission – maybe shut off because of a lack of a few thousands of dollars needed.
There is not much time left for NASA to come up with the funds before the planned Delta-V manoeuvre to the next target, Comet Boethin.
As part of a cost cutting strategy, NASA is also planning to shut down the two Voyager spacecraft which are now in interstellar space.
Mike Griffin, Administrator of NASA, has expressed concern at such actions.


__________________
Blobrana


L

Posts: 131433
Date:
RE: Deep Impact
Permalink  
 

Wep page

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 



-- Edited by Blobrana at 09:41, 2005-07-04

__________________
Blobrana


L

Posts: 131433
Date:
Permalink  
 

At 05:52 GMT the impactor collided with the comet.




__________________
Blobrana


L

Posts: 131433
Date:
RE: Deep Impact certificate
Permalink  
 

The names of 625,000 people will be part of the July 3-4 fireworks when Deep Impact impactor spacecraft collides with Comet Tempel 1.

When Deep Impact was in its final stages of development, organizers in NASA's Education and Public Outreach program created the Send Your Name to a Comet campaign.
The Internet-based effort allowed participants to sign their name up for destruction and print out an official certificate documenting their place on the list.

"We thought it would be fun for people to say their name was on the impactor that collided with the comet. We thought it would let them feel like they were part of the mission." - Maura Roundtree-Brown, organizer.

People could submit their names between May 2003 and January 2004.
Once registration closed, the list was burned onto a mini-CD and attached to the spacecraft -- tucked under the thermal blanketing.
But, no amount of thermal blanketing will protect the CD on this holiday weekend when the impactor and comet slam together at 37,000 Km/h.

"It will be vaporized along with the impactor" Roundtree-Brown.
While NASA will have to wait until Monday to see if they hit the mark with their impactor, Roundtree-Brown is pleased with the way the Send Your Name to a Comet campaign turned out.

"I was surprised how many people sent us emails and said that being able to submit their names to the impactor made them feel like they were part of the mission.
And that's why we did it -- because it would be fun for people to be connected to the mission." - Roundtree-Brown said.

My official certificate :smile:

__________________
Blobrana


L

Posts: 131433
Date:
RE: Deep Impact time
Permalink  
 

Nominal impact time is July 04 05:52:00 UTC, +/- 3 minutes, Earth received time.

The actual impact should occur about 07:15 minutes earlier due to the light time delay.

Current orbit solutions using astrometry determination from last night, says that impact will occur about 15 Seconds late. (The 1-sigma uncertainty is around 12 seconds)


__________________
Blobrana


L

Posts: 131433
Date:
RE: Deep Impact
Permalink  
 

Depending on the overall health of Deep Impact's Flyby spacecraft after monitoring Comet Tempel 1, a go/no-go decision can be made to send it on a 3.5 year cruise to Comet Boethin.

"We've been working on an extended mission" - Monte Henderson, Deputy Director of Programs in Civil Space Systems for Ball Aerospace & Technologies Corporation here. The company designed and built the two-part spacecraft specifically for the Deep Impact mission.

Comet Boethin orbits the Sun every 11 years. It was discovered on January 4, 1975 during a routine comet-hunting session carried out by the now deceased Reverend Leo Boethin of the Philippines.
Comet Boethin will be 0.87 AU from Earth on December 23 2008.

Shortly after Deep Impact's encounter with Comet Tempel 1, engineers will give the Flyby spacecraft a high-tech check-up. Particular attention will be paid to how much dust and debris that spews out from the comet has hit the Flyby craft.
Debris shielding is a key part of the Flyby spacecraft's design.
The Flyby spacecraft carries two of the three primary instruments, the High Resolution Instrument (HRI) and the Medium Resolution Instrument (MRI), for imaging, infrared spectroscopy, and optical navigation.
As the spacecraft passes through the inner coma of Comet Tempel 1 it is in danger of being struck by small particles that could damage the control, imaging and communication systems.

To minimize this potential damage the Flyby spacecraft is rotated before it passes through the inner coma. That debris shielding should provide, it is hoped, complete protection to the flyby spacecraft and its instruments.
The spacecraft's main deck serves as a back wall and an aluminium shield protects the Flyby spacecraft.

"After the encounter, we'll do a mini-commissioning of the Flyby spacecraft" - Monte Henderson.

If the reassessment is positive, a good portion of the remaining fuel on the Flyby vehicle will be used to put it on a 3.5-year jaunt to reach Comet Boethin. The redirecting manoeuvre would need to occur sometime before July 24.

"If we don't have good solid science instruments to use at Comet Boethin, we probably wouldn't want to expend our entire fuel budget. It would be more prudent to step back and figure out what else can we do" - Monte Henderson.

Given a healthy Flyby spacecraft, there is discussion at the Jet Propulsion Laboratory (JPL) in Pasadena, California of trying out autonomous navigation software.
Deep Impact's Principal Investigator, Michael A'Hearn at the University of Maryland, is also considering a request for proposals from the scientific community. Ideas will be welcomed, as to what other observations could be done with the Flyby spacecraft en route to zipping by Comet Boethin.
The "big sweaty palms" for the Deep Impact mission is getting the Impactor on its own.

"We've been able to test it via the umbilical through the Flyby spacecraft ... but the Impactor has never flown by itself" - Monte Henderson.

Then there's the issue of the high resolution telescope that's onboard the Flyby spacecraft. It is the largest telescope to fly in deep space and will record the details of the collision – but has a focus problem.
Deep Impact's high resolution telescope has experienced a "focus anomaly".

"It's an engineering accident and it is unfortunate" - Monte Henderson.

Engineers found after Deep Impact's launch that a reference flat used to calibrate the high resolution telescope's mirror on the ground did not accurately represent what cold temperatures the mirror would experience in space.

"After a lot of analysis with that mirror ... we essentially redefined what flat is for high resolution telescopes" - Monte Henderson.

If all this sound's a bit familiar, think Hubble Space Telescope. It too was initially focus-challenged. Eventually, the Earth orbiting observatory was outfitted with corrective optics thanks to a space shuttle servicing crew. For Deep Impact, there's no chance for any on-the-spot, hands-on help.

Experts at the Hubble Space Telescope Science Institute, however, had computer based algorithms – a way to de-blur and sharpen up Deep Impact images using a technique called deconvolution.
Through this process, Deep Impact's picture taking can be "massaged and tweaked" on the ground to greatly overcome the out-of-focus problem.
And as the $333 million Deep Impact mission closes in on its prey, Henderson said the team is ready for action.

"We've done test ... done everything we can be ready for. This is a one-time exciting event. It has been an engineering challenge, but also has a gee-whiz factor that seems to have captured a lot of public attention" - Monte Henderson.




__________________
Blobrana


L

Posts: 131433
Date:
RE: Submillimeter Array
Permalink  
 


Expand

The Submillimeter Array (SMA) will be ready and watching when NASA's Deep Impact probe strikes the nucleus of Comet Tempel 1 on July 4th. The impact is expected to excavate material from the comet's interior - material left over from the earliest days of our solar system.

"The SMA will be the only operational millimetre or submillimetre array observing Tempel 1 at the time of the impact. As such, there's no telling what we may see!" - astronomer Charlie Qi, Harvard-Smithsonian Centre for Astrophysics (CfA). "
Only a few observatories can study comets in the same wavelength regime as the SMA, but none match SMA's exquisite resolution. "The SMA will be the only submillimeter telescope in the world to make an image of the molecules released by the impact" - Glen Petitpas (CfA).

By observing submillimetre radiation, the SMA can "fingerprint" comets and determine their molecular composition. "SMA will observe mostly cool gas and dust with relative chemical abundances that may or may not be typical of other comets. We hope to see something NOT typical, because that would be most exciting to us scientifically" - Charlie Qi.

In the 1950s, the late Dr. Fred Whipple (CfA) developed the famous "dirty snowball" model for comets. Whipple hypothesized that comets consisted of ice with some dirt and rock mixed in. Modern astronomers believe that comets are better described as "icy dirtballs," containing more dirt and less ice than previously thought.
Deep Impact's mission is to test these new models by excavating a crater more than 80 feet deep and 300 feet in diameter, revealing the comet's pristine interior. Scientists will compare the freshly excavated material to the more easily visible cometary surface.

Ernst Tempel discovered Comet Tempel 1 in 1867. The comet has made many passages through the inner solar system orbiting the Sun every 5.5 years. This makes Tempel 1 a good target to study evolutionary change in the mantle, or upper crust, of the comet.

While the impending SMA observations of Deep Impact were a hot topic of discussion at this week's meeting on submillimetre astronomy held in Cambridge, Mass., Comet Tempel 1 is only one of the solar system objects that the SMA has studied.

Read More

__________________
«First  <  1 … 5 6 7 8  >  Last»  | Page of 8  sorted by
Quick Reply

Please log in to post quick replies.
Home -> Astronomy News -> Mission News -> Deep Impact


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard